Method and apparatus for production of subsea hydrocarbon formations

Abstract

A system for controlling, separating, processing and exporting well fluids produced from subsea hydrocarbon formations is disclosed. The subsea well tender system includes a surface buoy supporting one or more decks above the water surface for accommodating equipment to process oil, gas and water recovered from the subsea hydrocarbon formation. The surface buoy includes a surface-piercing central flotation column connected to one or more external floatation tanks located below the water surface. The surface buoy is secured to the seabed by one or more tendons which are anchored to a foundation with piles imbedded in the seabed. The system accommodates multiple versions on the surface buoy configuration.

What is claimed is: 
     
       1. A subsea well tender system comprising a surface-piercing surface buoy, wherein said surface-piercing surface buoy supports one or more decks above the water surface for accommodating equipment to process oil, gas, and water, and further including anchoring means securing said surface buoy to the seabed. 
     
     
       2. The system of claim 1 wherein said surface buoy includes at least one surface-piercing flotation column for supporting one or more decks above the water surface, and further including at least one flotation tank mounted to said surface-piercing flotation column. 
     
     
       3. The system of claim 2 wherein said anchor means comprises at least two tendons having one end anchored to the seabed and the other end connected to said surface buoy. 
     
     
       4. The system of claim 3 wherein said tendons include a tendon flotation buoy adjacent to each end of said tendons, and wherein said uppermost tendon buoy is dimensionally larger than said flotation tanks. 
     
     
       5. The system of claim 1 wherein said surface buoy includes at least two vertically oriented flotation tanks. 
     
     
       6. The system of claim 1 wherein said surface buoy includes at least two horizontally oriented flotation tanks. 
     
     
       7. The system of claim 1 wherein said surface buoy includes at least two diagonally oriented flotation tanks. 
     
     
       8. The system of claim 1 wherein said surface buoy includes flotation tanks forming a circular flotation ring. 
     
     
       9. The system of claim 1 wherein said surface buoy includes at least two levels of flotation tanks spaced one above the other. 
     
     
       10. The system of claim 1 wherein said surface buoy includes at least two substantially centrally located surface-piercing columns. 
     
     
       11. The system of claim 1 wherein said surface buoy includes a solid buoyancy slab mounted at the lower end of the surface piercing column. 
     
     
       12. The system of claim 1 including a deck structure mounted on the surface-piercing column above the water surface. 
     
     
       13. The system of claim 12 wherein the deck structure defines a prismatic shape connected at four corners to a spider deck mounted on said surface-piercing column of said surface buoy. 
     
     
       14. The system of claim 12 wherein said deck structure includes a downwardly extending section for stabbing into the uppermost end of said surface-piercing column. 
     
     
       15. The system of claim 12 wherein said deck structure defines a prismatic shape adapted for connection onto the top of said surface-piercing column. 
     
     
       16. The system of claim 1 wherein said anchoring means comprises a plurality of tendon segments connected end to end to form a single tendon string extending from the seabed to said surface buoy.